/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package de.google.android.apps.iosched.io;

import static de.google.android.apps.iosched.util.ParserUtils.queryItemUpdated;
import static de.google.android.apps.iosched.util.ParserUtils.sanitizeId;
import static de.google.android.apps.iosched.util.ParserUtils.AtomTags.ENTRY;
import static org.xmlpull.v1.XmlPullParser.END_DOCUMENT;
import static org.xmlpull.v1.XmlPullParser.START_TAG;

import de.google.android.apps.iosched.provider.ScheduleContract;
import de.google.android.apps.iosched.provider.ScheduleContract.Speakers;
import de.google.android.apps.iosched.provider.ScheduleContract.SyncColumns;
import de.google.android.apps.iosched.util.Lists;
import de.google.android.apps.iosched.util.SpreadsheetEntry;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.content.ContentProviderOperation;
import android.content.ContentResolver;
import android.net.Uri;
import android.util.Log;

import java.io.IOException;
import java.util.ArrayList;

/**
 * Handle a remote {@link XmlPullParser} that defines a set of {@link Speakers}
 * entries. Assumes that the remote source is a Google Spreadsheet.
 */
public class RemoteSpeakersHandler extends XmlHandler
{
	private static final String TAG = "SpeakersHandler";

	public RemoteSpeakersHandler()
	{
		super(ScheduleContract.CONTENT_AUTHORITY);
	}

	@Override
	public ArrayList<ContentProviderOperation> parse(XmlPullParser parser, ContentResolver resolver)
			throws XmlPullParserException, IOException
	{
		final ArrayList<ContentProviderOperation> batch = Lists.newArrayList();

		// Walk document, parsing any incoming entries
		int type;
		
		while ((type = parser.next()) != END_DOCUMENT)
		{
			if (type == START_TAG && ENTRY.equals(parser.getName()))
			{
				// Process single spreadsheet row at a time
				final SpreadsheetEntry entry = SpreadsheetEntry.fromParser(parser);

				final String speakerId = sanitizeId(entry.get(Columns.SPEAKER_TITLE), true);
				final Uri speakerUri = Speakers.buildSpeakerUri(speakerId);

				// Check for existing details, only update when changed
				final long localUpdated = queryItemUpdated(speakerUri, resolver);
				final long serverUpdated = entry.getUpdated();
				
				if (Log.isLoggable(TAG, Log.VERBOSE))
				{
					Log.v(TAG, "found speaker " + entry.toString());
					Log.v(TAG, "found localUpdated=" + localUpdated + ", server=" + serverUpdated);
				}
				if (localUpdated >= serverUpdated)
					continue;

				// Clear any existing values for this speaker, treating the
				// incoming details as authoritative.
				batch.add(ContentProviderOperation.newDelete(speakerUri).build());

				final ContentProviderOperation.Builder builder = ContentProviderOperation
						.newInsert(Speakers.CONTENT_URI);

				builder.withValue(SyncColumns.UPDATED, serverUpdated);
				builder.withValue(Speakers.SPEAKER_ID, speakerId);
				builder.withValue(Speakers.SPEAKER_NAME, entry.get(Columns.SPEAKER_TITLE));
				builder.withValue(Speakers.SPEAKER_COMPANY, entry.get(Columns.SPEAKER_COMPANY));
				builder.withValue(Speakers.SPEAKER_ABSTRACT, entry.get(Columns.SPEAKER_ABSTRACT));

				// Normal speaker details ready, write to provider
				batch.add(builder.build());
			}
		}

		return batch;
	}

	/** Columns coming from remote spreadsheet. */
	private interface Columns
	{
		String SPEAKER_TITLE = "speakertitle";
		String SPEAKER_COMPANY = "speakercompany";
		String SPEAKER_ABSTRACT = "speakerabstract";
		@SuppressWarnings("unused")
		String SPEAKER_LDAP = "speakerldap";
	}
}
